June 14, 1940 – World War II: The Soviet Union issues an ultimatum to Lithuania

On June 14, 1940, the Soviet government issued an ultimatumto Lithuaniato allow Soviet troops to enter Lithuanian territory and to form a newpro-Soviet government. Nine months earlier in October 1939, the two countrieshad signed the Soviet–Lithuanian Mutual Assistance Treaty that allowed thestationing of 20,000 Soviet troops in a number of bases inside Lithuania.

With the presence of Soviet forces already in the country,on June 15, the Lithuanian government acquiesced to the ultimatum and ended thecountry’s independence. The Soviets took control of the country, installed apuppet regime, and held sham elections to the legislature. The new legislatureproclaimed the establishment of the Lithuanian Soviet Socialist Republic andpetitioned to be admitted into the Soviet Union.In August 1940, the Soviet government accepted the petition and admitted Lithuania into the Soviet Union.

The Soviet Union signed similar mutual assistance agreementswith the other Baltic States, Estonia(September 28, 1939) and Latvia(October 5, 1939) that allowed Soviet forces to occupy specific bases in thetwo countries. Also in June 1940, Soviet forces occupied Estonia and Latvia;after socialist governments came to power in Soviet-controlled elections heldin July 1940, Estonia and Latvia were similarly incorporated into the Soviet Union in August 1940.